This disclosure relates, in general, to improvements in flush valves for toilets, urinals, and other plumbing equipment. More particularly, this disclosure relates to an improved diaphragm for use in flush valves.
Flush valves in toilets, urinals, and other plumbing devices may utilize a flexible diaphragm to both establish and seal off the connection between the inlet and outlet within a hollow brass body. In some flush valves, a barrel forms the connection between the inlet and outlet and the top of the barrel may include an annular main valve seat. This main valve atop the barrel may be normally closed by a flexible diaphragm which may extend across the hollow body of the flush valve and define an upper chamber. The flexible diaphragm may be clamped in place by an annular clamping rim on the flush valve body. The center of the flexible diaphragm may connect the upper chamber with the outlet, and a relief valve may be located in the center of the flexible diaphragm to normally seal off the upper chamber from the outlet.
Diaphragm assemblies may include the diaphragm, a relief valve, a stem, a guide member, wing members, a retaining disc, and a flow ring. The guide member in the barrel may move with the diaphragm and include outwardly extending radial wing members, which engage the inner surface of the barrel to guide the guide member and attached diaphragm. The guide member may be attached to the diaphragm with a retaining disc using brass threading. The diaphragm may be formed of rubber which may be bonded to the brass parts in order obtain acceptable seating surfaces.
In general, a normally closed flush valve may operate to seal off the upper chamber from the outlet using the water pressure from the inlet. The water under pressure at the inlet may communicate with the upper chamber of the flush valve through a bypass in the flexible diaphragm. Since the upper side of the diaphragm has a greater surface area, the water pressure forces the diaphragm down onto the valve seat on top of the barrel, thus preventing water from flowing into the outlet from the upper chamber. When a user moves a handle of the flush valve, a plunger may move inwardly toward the axis of the barrel and tilt a stem of the relief valve. This may break the seal the relief valve has established and allow water to flow through a guide member within the barrel and to the outlet. The opening of the relief valve may relieve the pressure within the upper chamber and the water pressure from the inlet may force the diaphragm upward and off of the main valve seat, allowing water to flow from the inlet through the barrel to the outlet. When moving upward, the diaphragm may reset the relief valve located in its center such that it again seals off the upper chamber from the outlet. Water from the inlet may then flow through the bypass into the upper chamber until the diaphragm is again forced against main valve seat, thereby closing the valve.